Best lefty off all time? My vote is Koufax!

[Snowman]

Originally Posted by Peter_Spaeth

I don't know, but if that's the case, doesn't that suggest a problem with your thesis (as I understood it) that for balls in play, all pitchers are pretty much the same and variances are just dumb luck (random) that will even out? And therefore it was a myth that some pitchers were better at pitching to contact.

So what's a guy like Maddux who doesn't strike out many batters doing with such a low SLG against? It seems meaningful? And walks don't come into the equation, so he isn't keeping SLG down by his lack of walks. That can only mean, I think, it has a lot to do with batters not getting as many extra base hits against him, which if true seems contrary to the thesis about pitchers not controlling where the ball goes after it leaves the bat.

BTW this is what you said that makes me think I am correctly characterizing your thesis:
The extent to which pitchers actually have this ability (referring to the ability to control the flight of batted balls) is miniscule at best. It's probably at least an order of magnitude less than people are thinking of when they make that claim. Maddux rarely walked hitters. He led the league in BB/9 9 times, and was probably in the top 3 15 times or more. This was his superpower.

Home run rates definitely account for some significant portion of slugging deltas between pitchers. And any pitcher can attempt to encourage fly balls vs ground balls simply by aiming higher or lower in the strike zone, or with breaking balls. But there's a trade off between the two, as ground balls drop in for hits at a slightly higher percentage but fly balls drop in for extra base hits at a higher rate despite being caught for outs more often (not to mention more home runs). I suspect this is probably what's responsible for any amount of control a pitcher has over their BABIP, however small that is. But they still have no control over how often those fly balls drop in for hits or how often those ground balls squeeze through gaps or become infield hits, etc. My understanding is that the tradeoff effectively balances itself out though in the grand scheme of things (e.g., run production), but I'd have to do more research.

I think there's a parallel here on the offensive side in terms of game theory strategy that we're all seeing across the league as batting averages drop but are traded off for more home runs.

Exactly how this balance effects BABIP values, you could figure out. But fly ball vs ground ball rates is almost certainly the best predictor of it. This is why I prefer using SIERA for evaluating pitchers. However, we don't have the data needed to calculate it for the prior generations of pitchers unfortunately. But for today, it's the best ERA statistic that I'm aware of, and one of the metrics I use in my models. It adjusts for fly ball and ground ball rates.